Kinguin is a really legit site, just look at their FB and twitter page. They have Steam, Origin, Desura (and other key sites) for FAR cheaper deals then on the official webshops. I am a long time costumer and they mail your key withing 10 sec. And all the keys you bought is stored in your account's library on their site (so look on in your game library rather than your mail, you might get they key faster this way)
What they do: you are a keyshop (but not well known), you have to fulfill some criteria (like being paypal secured etc) and tell kinguin to put their product on their site. This way, you as a costumer don't have to look all over the net to find the cheapest deals. This site gives you a list of all the webshops that offer this product and you just pick the cheapest one. And you pay via kinguin.
Big_Boss: Finally I wanted to try this site, and I bought Bioshock Infinite for 18€.
It was a US key, I activated and finished the game.
I hope Steam will not remove it, the seller had 200 positive feedback, so I hope this was a legit key.
Here the game costs too much, 50€ for PC version, 70 for console one.
even if the seller has 0 positive feedback don't worry about it. Means they are a new shop and kinguin only takes secure site and distributes their keys. Most shops that offer paypal, visa are secure these days. (though being cautious is always a good thing on the net)
jamyskis: Apologies for the minor necro again - I too have just used it with no problems. Delivery to my account took a few minutes after payment. The key was sold as worldwide, but oddly enough, it was delivered as a photo of the key sheet from a Russian retail copy. In any case, it redeemed fine as a ROW Steam key.
I remain sceptical, but at least on this occasion all went well.
Yeah well some of their keys are scanned from the retail box itself to show that the keys are genuine :p Not everything that is written in Russian (or any other foreign language) must be suspicious. They are a EU company so they have lot of European partners.